This invention relates to a guiding unit for agricultural products for a device for harvesting the agricultural products and a device for harvesting agricultural products comprising the guiding unit.
This invention is thus applied in particular in the agricultural sector, in particular in the harvesting of products performed immediately after the cutting (or mowing), or in a subsequent step.
Harvesting devices are normally used for picking up from the ground grass, straw, hay (also cut by other machines) or for picking up pulses and, in any case, for picking up similar agricultural products (usually plants), with a long shape.
For this purpose, they are connected to a pulling vehicle (such as a tractor or a self-propelled agricultural machine) which is used to tow them.
Prior art harvesting devices have a main axis of extension which, during use, remains transversal to the axis of movement of the pulling vehicle. To lift the agricultural products from the ground and move them (prior to unloading), harvesting devices use a plurality of harvesting elements associated therewith and driven by a movement system. The movement system is generally driven by a Cardan joint or the like which, through a power take-off, draws drive power from the engine of the pulling vehicle.
Each pick-up element is in turn provided with one or more juxtaposed tines. The pick-up elements (and the related tines) are usually positioned around the preferred axis of extension along rows parallel with the preferred axis of extension. Each pick-up element (and the related tines) is moved by the movement system along a closed trajectory surrounding the preferred axis of extension. The tines are straight elements with one end coupled (either directly or by means of parts of the respective pick-up element) to the movement system and the other end free.
Operatively downstream of the pick-up elements, devices of this type generally also comprise means for unloading the agricultural products harvested, usually consisting of movement devices, such as conveyor belts, chain conveyors or screw conveyors, located along the axis of extension of the pick-up device immediately downstream of the pick-up elements, in order to transport the agricultural products to the sides of the pulling vehicle.
It should be noted that each of the unloading means has a respective axis of movement, generally parallel to the main line of the frame, that is, transversal to the advancing axis.
Due to the type and the quantity, the products harvested tend to accumulate at the pick-up means, making the outfeed flow from the unloading means irregular and, in any case, causing problems linked to the clogging of the movement zones.
This may actually block the device or form piles with inconstant volumes, which may disturb the pick-up operation.
In this regard, guiding units have been introduced in these devices in the prior art which are able to facilitate the feed motion of the products in the pick-up means thus reducing the causes of malfunctions.
An example of these guiding units is shown in patent document EP2037727, which illustrates a guiding unit defined by a pair of arms pivoted to the frame of the device in such a way as to surmount the unloading means and provided, at their ends, with an array of combs which, in use, are facing the pick-up tines in such a way as to compact the products picked up, thus facilitating the harvesting.
More specifically, the arms are connected to the frame, at the rear of it, through a four-bar linkage which allows the inclination to be varied as a function of the quantity of products to be picked up.
Disadvantageously, this solution is complex from the constructional viewpoint since it requires the replacement of various components of the frame of the device and the design of structurally complex joints.
Moreover, the rotational movement of the guiding unit about a horizontal axis located to the rear of the unloading means does not allow a precise modulation of its action, since a rotation of the arm, even minimal, results in a very substantial translation of the combs.
Moreover, the use of that system does not allow a difference in the inflow of products in the various zones of the device to be taken into consideration, the position of the guiding unit being constrained to that imparted by the zone with the greatest density of products.